/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 *
 */
package org.apache.asyncweb.common.codec;

import java.nio.charset.CharsetDecoder;

import org.apache.asyncweb.common.HttpVersion;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.apache.mina.filter.codec.statemachine.ConsumeToCrLfDecodingState;
import org.apache.mina.filter.codec.statemachine.ConsumeToLinearWhitespaceDecodingState;
import org.apache.mina.filter.codec.statemachine.DecodingState;
import org.apache.mina.filter.codec.statemachine.DecodingStateMachine;
import org.apache.mina.filter.codec.statemachine.LinearWhitespaceSkippingState;

/**
 * Decodes a HTTP response line.
 * 
 * @author The Apache MINA Project (dev@mina.apache.org)
 */
abstract class HttpResponseLineDecodingState extends DecodingStateMachine {

	private final CharsetDecoder asciiDecoder = HttpCodecUtils.US_ASCII_CHARSET
			.newDecoder();
	private final CharsetDecoder defaultDecoder = HttpCodecUtils.DEFAULT_CHARSET
			.newDecoder();

	@Override
	protected DecodingState init() throws Exception {
		return READ_PROTOCOL_VERSION;
	}

	@Override
	protected void destroy() throws Exception {
	}

	private final DecodingState READ_PROTOCOL_VERSION = new HttpVersionDecodingState() {
		@Override
		protected DecodingState finishDecode(HttpVersion version,
				ProtocolDecoderOutput out) throws Exception {
			out.write(version);
			return AFTER_READ_PROTOCOL_VERSION;
		}
	};

	private final DecodingState AFTER_READ_PROTOCOL_VERSION = new LinearWhitespaceSkippingState() {
		@Override
		protected DecodingState finishDecode(int skippedBytes) throws Exception {
			return READ_STATUS_CODE;
		}
	};

	private final DecodingState READ_STATUS_CODE = new ConsumeToLinearWhitespaceDecodingState() {
		@Override
		protected DecodingState finishDecode(IoBuffer product,
				ProtocolDecoderOutput out) throws Exception {
			String statusCode = product.getString(asciiDecoder);
			try {
				out.write(Integer.parseInt(statusCode));
			} catch (NumberFormatException e) {
				HttpCodecUtils.throwDecoderException("Bad status code");
			}
			return READ_REASON_PHRASE;
		}
	};

	private final DecodingState READ_REASON_PHRASE = new ConsumeToCrLfDecodingState() {
		@Override
		protected DecodingState finishDecode(IoBuffer product,
				ProtocolDecoderOutput out) throws Exception {
			out.write(product.getString(defaultDecoder).trim());
			return null;
		}
	};
}
